Final answer:
Warren G. Harding was a visionary in the field of foreign policy negotiations, focusing on peace through international cooperation and armament reduction, best exemplified by his efforts in the Washington Conference.
Step-by-step explanation:
Despite the many well-founded criticisms of Warren G. Harding as president, he was a visionary for his era in the field of foreign policy negotiations. In the area of foreign policy, Harding worked to preserve the peace through international cooperation and the reduction of armaments around the world. After the U.S. Senate's refusal to ratify the Treaty of Versailles, Harding still managed to work with Germany and Austria to secure a formal peace. Moreover, he convened a Washington Conference that brought together world leaders to agree on reducing the threat of future wars by reducing armaments. The result was a series of treaties designed to foster cooperation and ensure a more peaceful international community.